Nitrocellulose of the grade, which is of effective and efficient use in a propellant, is preferably made from cotton for multi-base propellants, and sulfite wood pulp for single base propellants.
In the past, woodpulp of the sulfite variety has been found to be acceptable to produce nitropulp which could serve as a substitute for nitrocotton. But, due to the density of the sulfite pulp, it is difficult to nitrate. Thus, one cannot reliably get the same performance as nitro cotton. Further, sulfite wood pulp has a limited source of supply because it is currently available from only one U.S. manufacturer.
Woodpulp of the sulfate variety is of a more abundant supply when compared to the supply of wood pulp of the sulfite variety for which there is one source in the U.S. It also qualified, in time of war, as a source of woodpulp. However, in the past, it has been found that the sulfate variety of woodpulp is quite difficult to nitrate because of its density. In many cases, this leads to the rejection of the entire lot during processing.
It is an object of this invention to provide for the substitution of woodpulp of the sulfate variety for cotton in the process of producing nitropulp.
Another object is to provide for a more uniformly nitrated woodpulp of the sulfate and sulfite variety for use in propellants.
A further object is to provide for more effective washing of the fibers of nitropulp of the sulfate and sulfite variety, and a more efficient recovery of the spent nitrating acid solution.
Another objective is to increase the production capacity of existing manufacturing facilities by 25% by expanding the use of wood pulp and sheeted cotton linters which have nearly twice the through put capability.
A still further object is to eliminate the need for costly pollution abatement equipment and operating expenses from the process of nitrating woodpulp of the sulfate and sulfite variety.
These and other objects will become more apparent from a reading of the following detailed specification.